GaussBonetTheorem 2007-01-26 10:10:33 2009-11-15 02:32:34 Theorem % this is the default PlanetMath preamble. as your knowledge % of TeX increases, you will probably want to edit this, but % it should be fine as is for beginners. % almost certainly you want these \usepackage{amssymb} \usepackage{amsmath} \usepackage{amsfonts} % used for TeXing text within eps files %\usepackage{psfrag} % need this for including graphics (\includegraphics) %\usepackage{graphicx} % for neatly defining theorems and propositions %\usepackage{amsthm} % making logically defined graphics %\usepackage{xypic} % there are many more packages, add them here as you need them % define commands here If $S$ is a compact, orientable surface without boundary, then $$ \int_S K=2\pi\,\chi(S), $$ where $K$ is the Gaussian curvature of $S$ and $\chi(S)$ its \PMlinkname{Euler-Poincar\'e characteristic.}{EulerrCharacteristic}